Hopeman, R. J. (1971). Production: Concepts, analysis, control (2nd ed.). Merrill.
Lua i Stíl Chicago (17ú heag.)Hopeman, Richard J. Production: Concepts, Analysis, Control. 2nd ed. Columbus, Ohio: Merrill, 1971.
Lua MLA (9ú heag.)Hopeman, Richard J. Production: Concepts, Analysis, Control. 2nd ed. Merrill, 1971.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.